The Hobbit, The Lord of the Rings, The Silmarillion, The Histories of Middle Earth, all lore related to this universe is acceptable fodder. Regardless of their power, susceptibility to The One Ring, amount of appearances, or any other constraint, who or what is the oldest?

Since Eru is the "easy" answer, then who or what is second? Any canon source, including letters, is acceptable.

And if it matters, the criteria would be oldest at the end of LotR or whatever place he left off in his tales whether the being was alive or not at that point. Example: if being 1 was 999 years old at point A and died, and being 2 was 998 at point B (years after point A) and died, being 1 was oldest in the lore.

(I am not well-read in the Histories and letters and such. If he continued the tale much past the end of LotR, then that is the cut-off point. Oldest sentient being, alive or dead, at the end of canon.)

If you have a question about if some source counts, ask yourself: Did it come from JRR or Christopher working from his father's notes? If the answer is Yes, then it counts. If it does not come from the family, then no. I can trust scholars, but would like the trail to be only one degree of separation. If your case is compelling enough, a pass may be granted.

EDIT

If it's not bad form, can I extend the question to the oldest four? Eru is too obvious and as Kevin comments, "Eru was clearly first, he created the ainur second, and it's generally indicated that Tom Bombadil is tied to Middle-Earth and so third." The "generally indicated" thing is not decisive, but, if this is indeed accurate, I'm curious to know just a little bit more. Please either play along with me, or slap my hand for grabbing too many cookies. It's a fascinating and complicated history I know too little about. (I do plan to remedy this someday.)

NEWER EDIT

I just noticed this question still gets viewed and was active a few months ago. Let me further clarify. I am after the oldest entity AT ANY POINT in the canon. If a creature lived to be 99 years (I'm using low numbers to keep it simple) and then died, and another lived to be 98 at the close of the canon, the dead one wins. Living, dead, doesn't matter. Age at end of canon is all that counts.

12 Answers
12

Eru created the Ainur and they sang the world into existence, presumably including Tom Bombadil so yes, the Ainur would be the eldest after Eru. Since Bombadil is in essence an Earth elemental and tightly tied to Middle Earth, he could only be as old as the world itself and so younger than the Ainur (and the Maia like Gandalf).

Another contender would be Ungoliant whose origins are unclear. The Silmarillion states (emphasis mine):

The Eldar knew not whence she came, but some have said that in ages long before she descended from the darkness that lies about Arda, when Melkor first looked down in envy upon the Kingdom of Manwë, and that in the beginning she was one of those that he corrupted to his service.

This suggests that she was somehow from outside the world and perhaps even independent of the Ainur's song (or even Eru himself?). I read the Lost Tales years ago and don't remember but according to this:

In The Book of Lost Tales, Ungoliant's history is even more mysterious then what is implied in the published edition of The Silmarillion. Here, even the Valar did not know of her origins, and she was portrayed as a primeval spirit of night, and believed to be a creature bred of the darkness of the Void.

This suggests that she is indeed independent of the Ainur (the Valar) and might be older then they. Finally, I found this page that states:

"Within this structure there are as almost always a great many points of difference between the first story and the later versions." "In the tale her origin is unknown, and though this element may be said to remain in The Silmarillion ('The Eldar knew not whence she came', ibid.), by the device of 'Some have said....'a clear explanation is in fact given: she was a being from 'before the world', perverted by Melkor, who had been her lord, though she denied him. "

and

"Mayhap she was bred of mists and darkness on the confines of the Shadowy Seas, in that utter dark that came between the overthrow of the Lamps and the kindling of the Trees, but more like she has always been; ...."

So, at the very least she seems to be as old as the Ainur but may be older still.

Wow. Nice work. +1! I'm waiting on more answers but this is intriguing.
– Meat TrademarkFeb 19 '14 at 19:13

2

But Ungoliant is believed to be dead by the timeframe of The Lord of the Rings (either she devoured herself or was killed by Eärendil), and so she doesn't count for this purpose.
– Mike ScottFeb 19 '14 at 20:07

5

Also, the Maia can't be younger than the Ainur, because they are Ainur -- the Ainur include the Valar, the Maia and many more Ainur who never entered the world.
– Mike ScottFeb 19 '14 at 20:09

1

@MikeScott the time frame of LOTR is tiny, less than a hundred years so I don't think that makes much of a difference, but yes, she was dead by then (we guess). As for the Maia being younger, again good point, it's been a while since my last reading of the Silmarillion and I thought that the Maiar were created by the Ainur's song. Answer edited, thanks.
– terdonFeb 19 '14 at 20:16

The best answer one can give is "it depends". First question: are we counting as of the beginning of the series, or as of the end? Or are we looking for the longest-lived character, regardless of whether or not they're still alive by the time of the books?

If we count everyone who appears in the trilogy or the Silmarillion, then it would be Eru (i.e. the Creator), or possibly Tom Bombadil. But Eru doesn't appear in the trilogy directly, and it is hard to imagine Tom Bombadil winning out here unless he is Eru: a theory espoused by some fans, though Tolkien himself is said to have disliked it.

If we leave out Eru as being unfair, then it goes to Melkor (who became Morgoth), or one of the Valar, or possibly Tom Bombadil. But these were created before Arda, when time had no meaning, so we have to be careful about where we start counting. If we look at when they arrived in Arda, then it is likely either Melkor or Manwe. Though if we assume that Morgoth's exile to Outside means he no longer counts (though he is still technically alive) then Manwe wins pretty much by default. However, none of this occurs in the trilogy per se.

If we leave out Silmarillion-only characters, then depending on how we define a few things, it would be mostly a tie between the various Maiar: Saruman and the other Wizards, Sauron, and possibly Tom Bombadil (are you starting to notice a theme here?) The spiritual nature of these creatures requires us to define a few things, though. Curunir (who became Saruman) is called the "eldest" of the Istari, but the Maiar have a similar problem to the Valar: they were created when time had no meaning. Given this, is "eldest" really a literal measure of age, or does it refer to some other kind of ranking? Do we instead consider, not their actual creation, but the time when they entered Arda, or possibly Middle-Earth, in which case we'd need to know the order in which they arrived? Does Sauron count as "alive" at the end of the series, even though he can no longer take form, and does that even matter to the question?

If we leave out the "spirits" -the Ainur and similar beings- then we're left with life-forms: Elves, Men, and their ilk, and, yes, possibly Tom Bombadil. But Elves complicate matters, because they are immortal: some do indeed die, but should we count those who traveled to the Undying Lands as "dead" for this question? In any event, Cirdan is likely the oldest Elf still outside the Undying Lands: he may have been among the first generation of Elves, and the only other Elf we hear of who even comes close to him in age -Galadriel- is his grandniece.

If we leave out the immortals, then we deal with beings who have finite lifespans: Ents, Eagles, Men, and so on. The honor here likely goes to Treebeard, Old Man Willow, or possibly -you guessed it- Tom Bombadil. Treebeard is the oldest living Ent, and one of the first generation, which appeared at around the same time as the Elves (though we do know the Elves came first). Old Man Willow might predate even him, particularly if we count time spent as a mere tree before gaining sentience. But Tom Bombadil claims to remember even things like "the first acorn", so if he still counts for this form of the question, he must beat even Old Man Willow.

And here is the problem: when dealing with Tolkien's most ancient characters, the concept of "age" starts to break down. Your question could have many answers, depending on what exactly you mean to ask.

Of the Elves, Daeron makes a fleeting appearance in Appendix E. According to the Annals of Aman he invented his runes in VY 1300 (so he was born some indefinite time earlier) whereas Galadriel was born in VY 1362. Now, Of Beren and Lúthien states that during the Quest of the Silmaril he "came into the East of Middle-earth, where for many ages he made lament beside dark waters for Lúthien", so probability is that he's still alive at the time of LotR. That ranks him before Galadriel, but Círdan is still older.
– user8719Mar 13 '15 at 23:45

Tom Bombadil is called by the elves Iarwain Ben-adar, meaning "Oldest and Fatherless", which implies that he's at the very least the oldest being that the elves know of. Since we know so little about Bombadil ourselves, it's hard to assess the accuracy of this.

Other than the wild card of Bombadil, the Ainur were the first beings created by Eru Iluvatar. Since I don't believe we know anything about the order in which they were created, all the Ainur must be considered as being equally old.

Now I'm getting greedy with my edit, but I have to ask: Why was this a comment and not answer, Kevin?
– Meat TrademarkFeb 19 '14 at 19:16

1

It seems likely that Eru was the first (it is said Eru was there, the one... of course that doesn't exclude there couldn't be someone else in another place, after all "one" makes no sense when there can't be "two"), and it is clearly told that he created the Ainur and sang to them, blah blah. However, when the Ainur descend into the world, it is said that with them came a lot of spirts and beings. No mention whence they came from. Did Eru create them, or did they come from somewhere else? Were they there first? We don't know. Ungoliath seems to have come from "nowhere", for example.
– DamonFeb 20 '14 at 0:22

Cirdan is the oldest named Elf at the end of Lord of the Rings, who takes part in events.

HoME 12 notes that his original name was "Nowe", which is an archaic form with an uncertain original meaning. It also discusses his pre-eminence as a ship-builder, even during the Teleri's stay on the shores of the Sea of Rhun during the Great March. These, taken together with his relationship to Elwe and Olwe, make it almost certain that he dates to Cuivienen, although whether he was one of the First or a later generation is uncertain.

The first three (male) Elves to awake were named Imin, Tata and Enel, who each awoke with their designated spouse (as did all of the First). By contrast, the leaders of the three clans of the Eldar were Ingwe, Finwe and Elwe.

Ingwe is probably not Imin

This is deduced from writings in HoME 10, where Indis of the Vanyar is noted as being Ingwe's sister (therefore they had parents and couldn't have been among the First). These weren't taken up in the published Silmarillion.

Finwe is not Tata

Finwe married Miriel

Miriel had a mother-name

Therefore Miriel had a mother

Therefore Miriel wasn't one of the First

Therefore Miriel couldn't have been Tata's designated spouse

Elwe is not Enel

Elwe had two brothers: Olwe and Elmo

Therefore Elwe (and his brothers) had parents

Also, Elwe married Melian

Therefore Elwe didn't have a designated spouse

Finwe and Elwe are also not among the First (on the designated spouse criteria), but Ingwe may be if we reject Indis as his sister.

If we accept Indis as Ingwe's sister, then Ingwe is not one of the First even if we stretch the definition of "sister", as otherwise Indis would have also had her own designated spouse and therefore would not have been able to marry Finwe.

All of the first clan became Eldar, therefore Imin was either captured by Melkor or he left for Aman. Half of the second clan and about two-thirds of the third clan became Eldar, with the rest remaining as Avari. Tata and Enel may have become Eldar or Avari; it's not stated anywhere. Either way (and unless they were captured by Melkor - which is also possible), they're still around at the time of LotR; they just don't come into the stories.

It can be fairly assumed that Ingwe and Olwe still live at the end of LotR and would therefore also qualify, along with Cirdan, as being among the oldest living sentient beings. Ingwe was one of the three Elves who visited Valinor with Orome and returned to convince the Elves to go; Olwe was one of the two leaders (with his brother Elwe) of the Teleri on the march west (see the Silmarillion, Of the Coming of the Elves and the Captivity of Melkor). As of the end of the Silmarillion, both Ingwe and Olwe were the kings of their respective people in Valinor.

Galadriel is the only one left of the leaders of the Noldor who took part in the rebellion (Letter 297). Glorfindel and Gildor Inglorion are of course also noted as Noldor. There are variant stories about the history of Celeborn, but published writing notes him as a kinsman of Thingol who lived in Doriath. He may or may not date back to the Great March or even Cuivienen. Thranduil also goes back to Doriath, and Legolas may even be of similar vintage (he does immediately recognise the Balrog, and Tolkien notes in Letter 144 that "it is observable that only the Elf knows what the thing is" - thin evidence but evidence nonetheless).

Among the Dwarves the various reincarnations of Durin should be considered, although they don't directly take part in events of LotR. However, if Dwarf myths are true, one could argue that Durin was originally incarnated (by Aule, then by Iluvatar) before the Elves.

Treebeard claims to be one of the first Ents that were awoken by the Elves:

Only three remain of the first Ents that walked in the woods before the Darkness: only myself, Fangorn, and Finglas and Fladrif (Two Towers)

This makes him quite old indeed, comparable in age to Cirdan at least. However, he also notes that there are other trees around that are even older than he is:

But there are hollow dales in this land where the Darkness has never been lifted, and the trees are older than I am. (Two Towers)

Treebeard is a character in my story, not me; and though he has a great memory and some earthy wisdom, he is not one of the Wise, and there is quite a lot he does not know or understand.

Gwaihir and Landroval date to the First Age; the 1937 Silmarillion names them as two of the Eagles that rescued Beren and Luthien from Angband, but Christopher Tolkien suppressed the names in the published Silmarillion based on evidence he has since rejected. This is all discussed in HoME 5.

There's no indication as to whether or not Thorondor is still alive. He may be the Lord of the Eagles in the Hobbit; we know that the Lord is not Gwaihir, because Gwaihir had only carried Gandalf twice before the destruction of the Ring ("Twice you have borne me, Gwaihir my friend" - RotK - from Isengard and Zirak-zigil), yet the Lord had carried Gandalf in the Hobbit.

Ungoliant is old, but probably not as old as another answer indicates. Let's have the Silmarillion quote again, but with different emphasis:

The Eldar knew not whence she came; but some have said that in ages long before she descended from the darkness that lies about Arda...

It should be obvious that this story of her origin is therefore a legend of the Eldar, and not an authorial statement by Tolkien. Her most likely origin is a corrupted nature spirit, as outlined in Of Aule and Yavanna:

When the Children awake, then the thought of Yavanna will awake also, and it will summon spirits from afar, and they will go among the kelvar and the olvar, and some will dwell therein, and be held in reverence, and their just anger shall be feared.

Shelob dates to at least early Second Age: "but still she was there, who was there before Sauron, and before the first stone of Barad-dur" (Two Towers) - with "there" being Mordor, and Barad-dur being begun in SA 1000 (RotK Appendix B).

Not forgetting:

There was Eru, the One, who in Arda is called Ilúvatar; and he made first the Ainur, the Holy Ones, that were the offspring of his thought, and they were with him before aught else was made.

And you can throw Bombadil into that wherever best suits your own favoured theory as to who or what he is.

Nice answer. I might also note that it can be fairly assumed that Ingwe and Olwe still live at the end of LotR and would therefore also qualify, along with Cirdan, among the oldest living sentient beings. Ingwe was one of the three Elves who visited Valinor with Orome and returned to convince the Elves to go; Olwe was one of the two leaders (with his brother Elwe) of the Teleri on the march west. (See the Silmarillion, Of the Coming of the Elves and the Captivity of Melkor.) As of the end of the Silmarillion, both Ingwe and Olwe were the kings of their respective people in Valinor.
– RobFeb 20 '14 at 1:29

In "The Lhammas" in The Lost Road it says, "Ingwë, high-king of the Eldalië, and the oldest of all Elves, for he first awoke", which suggests that he should be identified with Imin.
– Mike ScottFeb 20 '14 at 7:59

@MikeScott - but is the information in the Lhammas still to be considered valid, or is it superseded by later works? The Lhammas predates the shift from Gnomish to Sindarin, Elwe is not Thingol, Quendian languages are derived from Valian, most of the Avari (there called the Lembi) were Teleri (in later stories most Avari were actually second kindred) - I'd be extremely careful before attaching any authority to anything in the Lhammas.
– user8719Feb 20 '14 at 9:26

I believe it must be Tom Bombadil?
So old that even the Ring has no power on him?
Sadly we read so little of him though.

"Eldest, that's what I am... Tom remembers the first raindrop and the first acorn... He knew the dark under the stars when it was fearless - before the Dark Lord came from Outside."
—Tom Bombadil (The Lord of the Rings)

And he is older than Sauron

Tom Bombadil was in the world when the Elves passed westward before the seas were bent. He knew the dark under the stars when it was fearless – before the Dark Lord came from Outside.

Even Elrong agrees that he is the oldest

"But I had forgotten Bombadil, if indeed this is still the same that walked the woods and hills long ago, and even then was older than the old."
—Elrond, The Fellowship of the Ring

You can check these books: "The Letters of J. R. R. Tolkien" and "The Adventures of Tom Bombadil" or feeling lazy? Check his wiki
Also read theoris about him

You believe it to be Tom? Can you cite any evidence? I'd suggest looking at the Tour under the help menu above. Hint: since reading the Tour gives you a badge, and you have no badges, it's obvious when someone has not read it. ;)
– Meat TrademarkFeb 18 '14 at 16:09

Welcome to site, friend. Nice badges, by the way. Whether you're right or not +1 from me for not being discouraged and giving it a go. (It's a start, 10 points is ten points, right?)
– Meat TrademarkFeb 19 '14 at 8:55

1

After reading The Silmarillion, I always took Bombadil's reference to "the Dark Lord [who] came from Outside" as a reference to Morgoth, not Sauron. He also remembers the first raindrop and acorn. All of that would place Bombadil in Creation at the same time as the Ainur, or even before.
– dmmMay 11 '15 at 18:26

Morgoth came from outside, but we don't know how long he existed outside before coming to Arda.
– XalorousNov 18 '16 at 21:37

The oldest character in Lord of the Rings is either Saruman or Sauron. They are both Maiar, Ainur who entered Aman at the very beginning of time. They're essentially demi-gods. They are similar to the Valar, the Ainur who participated in the creation of the universe, but they're likely less powerful.

Note that I don't include Gandalf as a possibility, since the Silmarillion makes clear that Curunir (Saruman) was the eldest of the Istari (wizards):

Of these Curunir was the eldest and came first, and after him came Mithrandir and Radagast, and others of the Istari who went into the east of Middle-earth, and do not come into these tales.

Not enough is known about Tom Bombadil. There are a lot of theories that he could be Eru, or maybe a Valar, or even just a natural spirit like the Elves. But he's a huge question mark and it's impossible to be sure.

If you're asking who the oldest non-deity is, in the books, it's almost certainly Cirdan the Shipright. He was so old that he participated in the Great Journey of the earliest elves from Middle-Earth to Valinor ("The West"), although he and his fellow Sindarin elves turned away from the journey before leaving Middle-Earth. This was sometime early in the First Age, making him probably at least 7,500 years old in Lord of the Rings. He wasn't mentioned by name in the movies, but he was in the background of the final scene, when Frodo and the others are boarding a ship to leave.

There's also some possibility that Glorfindel is about the same age as Cirdan. Tolkien made some statements indicating that he was considering Glorfindel (who appears in the books as the powerful elf who rushes Frodo to Rivendell -- instead of Arwen) to be the same as an elf of the same name active in the Silmarillion during the First Age. The LotR Wikia has a bunch of discussion.

Curunir being the eldest may not be related to its age as a Maia, but to its coming to Middle Earth. Probably all Maiar were created at the same time.
– EnviteFeb 18 '14 at 15:54

2

I think you've massively underestimated Círdan's age here. There were 400 "Years of the Trees" between the beginning of the Great Journey and the first rising of the Sun, and then 7000 years until the War of the Ring. But the Years of the Trees were at least 10 times, and possibly 100 times, as long as normal years, making that duration at least 4000 years.
– Daniel RosemanFeb 18 '14 at 16:30

The First Age and the Years of the Trees coincided somewhat -- the First Age began when the elves awoke. But, yes, 7,500 years is a minimum.
– PlutorFeb 18 '14 at 17:40

Bombadil was known by the elves as Iarwain Ben-adar, "Oldest and Fatherless". The clue is in the name.
– Mike ScottFeb 18 '14 at 18:14

"Eldest of the Istari" most likely just means the first Maia chosen to be an Istar - which the Istari essay in UT indicates was Curumo/Saruman.
– user8719Feb 18 '14 at 20:46

Outside of the Ainur, who came into existence before the beginning of the world, there are a few contenders still living in Aman or Middle-Earth by the Third Age:

Galadriel. Daughter of Finarfin, son of Finwe. She crossed Helcaraxe when the Noldor returned to Middle-Earth, before the creation of the Sun or the Moon.

Older than she may be

Cirdan. He is a Teleri who never saw Aman. I'm not aware of his lineage, and he may well be one of the elves who awoke at Cuivienen.

More documented than Cirdan is

Ingwe. He is the king of the Vanyar and considered High King of the elves. He almost certainly awoke at Cuivienen, but never returned to Middle-Earth.

As is touched on with the creation myth of the Dwarves, Eru was jealous of any (non-Ainu) beings coming into the world before the Elves. So, it seems a living elf who woke at Cuivienen is the oldest you can get.

You're forgetting Bombadil, the Ents and Old Man Willow all of whom were almost certainly present in Middle Earth before the Elves crossed the sea.
– terdonFeb 19 '14 at 20:22

True enough. Bombadil is a transplant from Tolkien's other works, and he kept Bombadil mysterious intentionally. As such he doesn't fit well into any category. I have no reason to believe Old Man Willow is not a Maia. We don't know when the Ents appeared, but being created by Eru (who expressed a desire that the First Born be first), it seems safe to guess they came shortly after the elves.
– phsFeb 19 '14 at 20:27

Old Man Willow a Maia? Why? He is a tree that has awoken, possibly an old Ent, nothing to do with the Maia. I have always taken Tom to be an Earth elemental, so as old as the planet but that's just my take on him. I had thought that Ents were as old as the Earth (the planet anyway) as well but I just checked and I was wrong, you're quite right, they're as old as the Elves.
– terdonFeb 19 '14 at 20:31

Flaunting my ignorance here. As a tree awoken, Tom's claim to have seen the first acorn is a little problematic, if Tom is to be trusted.
– Meat TrademarkFeb 19 '14 at 20:57

3

Tom in general is a problem. If we leave him on the table then all bets are off on many questions (who would win in a fist fight, etc.) For that reason I'm opting to ignore him.
– phsFeb 19 '14 at 20:58

The answer depends on what is signified by oldest. If you take oldest to mean oldest in their existence in the world, then Tom Bombadil and others beings of his ilk qualify to be called the oldest in Arda. These were the oldest beings in Arda

Ungoliant

Tom Bombadil

Possibly the Watcher in the Water

Many other unnamed entities lurking in the deep places of Arda.

In fact Tom Bombadil states unambiguously from his point of view that he was there in Arda before the Dark Lord (Morgoth).

"Eldest, that's what I am... Tom remembers the first raindrop and the
first acorn... He knew the dark under the stars when it was fearless -
before the Dark Lord came from Outside."—

Tom Bombadil (Fellowship of the Ring)

How could a creature or being in Middle Earth be older than one of the Ainur who we know are spirits created by Eru before the creation of the World? This would be possible only if Tom and other beings like him were created with Ea and were inseparable parts of the World in the thought of Eru Iluvatar. Thus to him, Melkor and the other Ainur would be outsiders who appeared later on Arda.

In Tolkien’s universe, the Ainur are those spirits which were with Eru, the Creator before the creation and participated in the Song of Creation. They were meant to be active participants in the making and shaping of the world. But not all spirits in Arda could belong to the category of Ainur. Arda is populated by various other spirits which were not Ainur but came into being with the creation of the World. These beings didn't participate in the Song of the Ainur because they didn't exist before the creation of the world. They were beings created with the World as an embodiment of certain archetypes.

Though the Ainur being products of Eru Iluvatar's thought had existed outside of the created world as expressions of various aspects of His Mind, it is only after the creation of Ea that they (Ainur) enter Time and Creation.Thus they would innately be less "older" compared to the beings which were created with the World and had always been a part of it.

Ungoliant who allies with Melkor to destroy the two trees is one of these other spirits.

Some have said that in ages long before she (Ungoliant) descended from
the darkness that lies about Arda […] in the beginning she was one of
those that he corrupted to his service. But she had disowned her
Master

– The Silmarillion, ‘Of the Darkening of Valinor’; Chapter 8

She is the archetype of primordial darkness and the Void and her trying to devour Melkor foreshadowing of Melkor’s ultimate fate of being cast out into the Void.

The Watcher in the Water, the creature the Fellowship encounters at the gates of Moria was another of primordial "other" spirits.The name “Watcher in the Water” itself seems to suggest that this being’s existence was inextricably bound to the waters and that it was a guardian for the lakes beneath the mountain.

“I felt that something horrible was near from the moment that my foot
first touched the water,' said Frodo. 'What was that thing, or were
there many of them?'

'I do not know,' answered Gandalf; 'but the arms were all guided by
one purpose. Something has crept, or has been driven out of dark
waters under the mountains. There are older and fouler things than
Orcs in the deep places of the world.' He did not speak aloud his
thought that whatever it was that dwelt in the lake, it had seized
upon Frodo first among all the Company.”

-The Fellowship of the Ring, Chapter 4 "A Journey in the Dark"

The existence of beings other than the Ainur in the "deep places of the World" is also hinted at by Gandalf in his words to his companions.

And this

Far, far below the deepest delvings of the Dwarves, the world is
gnawed by nameless things. Even Sauron knows them not. They are older
than he. Now I have walked there, but I will bring no report to darken
the light of day.

-The Two Towers Book III , Chapter 5: "The White Rider"

Thus we can conclude from examples scattered throughout the text that there were indeed beings older than the Ainur in Arda that were “nature spirits” whose very existence was tied up with the World.

One should note that looking at the Silmarillion, the Valar and their Maiar probably did work for aeons on Arda before Melkor came: "And the Valar drew unto them many companions, some less, some well nigh as great as themselves, and they laboured together in the ordering of the Earth and the curbing of its tumults. [...] And [after he saw what they created!] he [Melkor] descended upon Arda in power and majesty greater than any other of the Valar...". Melkor waited in the void and Tom may very well be "eldest in Middle-Earth", saying he was among the first spirits and stayed.
– Philip KlöckingNov 18 '16 at 13:41

According to the statement made by Elrond while they were discussing what to do with the One Ring, he says that if Sauron gets the ring that Tom Bombadil(whatever Tom was) would fall last as he was first. I interpret that to mean that Tom was the oldest sentient being - at least in Middle Earth. As others have pointed out, if you want to be strict about things, Eru would be the obvious choice according to the Silmarillion - followed, of course, by the Ainur and Maia. The comments about Ungoliant are intriguing but things are murky enough that it's difficult to determine just where she actually fits.

Cirdan clearly had a much longer history in the First age than Galadriel. He was clearly much older than Galadriel. Cirdan supposedly told Gandalf he would wait on the shore until the last ship sailed. The Return of the King, Appendix II "The Tale of the Years", the Third Age.

In Return of the King Book VI chapter6 "Many Partings" Celeborn told Treebeard " I do not know, eldest." Implying that Treebeard was the oldest living member of the group (not counting Gandalf's age as a maiar before incarnation) and possibly the the oldest living being then on Middle-earth (since Tom Bombadil might not have been entirely a living being).

However, Treebeard and the other two oldest Ents may have died in the Fourth age and left Cirdan or Celeborn the oldest living being on Middle-Earth. The Note on the Shire Records in the Prologue to The Fellowship of the Rings says that there is no record of the date when Celeborn at last sailed to Valinor "and with him went the last living memory of the Elder days in Middle-Earth". This implies that Celeborn, or one of his companions such as Cirdan, was the oldest living person in Middle-earth at that time and after Celeborn left nobody was left on Middle-earth who had been alive in the First Age.

Tom is the oldest living being in middle earth. He was there even before the Valar arrived. So even if the Valar are older than Tom, he is still the eldest being on Arda, having been there since the beginning.

To clarify, Ungoliant would be the oldest, for she is/was timeless evil but was supposedly killed by Earendel, so is no longer in existence, I do not know how to classify Bombadil, so for the sake of this argument Galadriel is oldest Lord of the Rings character, but Gandalf (in the form of Olorin) and Sauron probably existed long before her in Maia form and Manwe was oldest and first of the Ainu.

-1; the question is "Oldest sentient being at the end of Tolkien's lore" so a character who was killed in the First Age doesn't count.
– user8719Mar 3 '15 at 12:56

I meant who was the oldest, or existed the longest, at the end of the lore. Not just who was alive. If something was 99999 but died earlier, and the the surviving oldest was 99998 at the end of the narrative, 99999 wins.
– Meat TrademarkSep 5 '15 at 16:08